Vector magnetometer based on the effect of coherent population trapping.

The method is presented for converting a coherent population trapping (CPT) atomic clock into a CPT vector (compass-) magnetometer without mechanically moving parts through a relatively simple add-on. The system of 3D Helmholtz coils was used for compensation of the external magnetic field, allowing measurement of both strength and direction of a magnetic field at the sensitivity level of -/ within a 10-Hz bandwidth. Angular resolution of the developed vector magnetometer amounts to about 10 degrees.

Efficiency of different methods of extra-cavity second harmonic generation of continuous wave single-frequency radiation.

This work presents for the first time to the best of our knowledge a comparative efficiency analysis among various techniques of extra-cavity second harmonic generation (SHG) of continuous-wave single-frequency radiation in nonperiodically poled nonlinear crystals within a broad range of power levels. Efficiency of nonlinear radiation transformation at powers from 1 W to 10 kW was studied in three different configurations: with an external power-enhancement cavity and without the cavity in the case of single and double radiation pass through a nonlinear crystal. It is demonstrated that at power levels exceeding 1 kW, the efficiencies of methods with and without external power-enhancement cavities become comparable, whereas at even higher powers, SHG by a single or double pass through a nonlinear crystal becomes preferable because of the relatively high efficiency of nonlinear transformation and fairly simple implementation.

240-GHz continuously frequency-tuneable Nd:YVO₄/LBO laser with two intra-cavity locked etalons.

This work reports for the first time on study of a single-frequency Nd:YVO4 laser with intra-cavity frequency doubling, in which quasi-continuous frequency tuning over an ultra-broad range is implemented with two intra-cavity locked etalons and automatic stitching between ranges of smooth scanning of the laser's output frequency. The proposed and demonstrated method allowed to continuously tune the output frequency of the studied 1.5-W Nd:YVO4/LBO laser over a record-breaking broad range of 240 GHz at 532 nm.

Variable-wavelength second harmonic generation of CW Yb-fibre laser in partially coupled enhancement cavity.

This work for the first time proposes and studies a method of frequency doubling of CW non-single-frequency fibre lasers with a high-Q resonator partially coupled to the fibre laser cavity. The proposed new approach resulted in the following parameters: laser's maximal output power 880 mW at 536 nm when pumped with 6.2 W at 976 nm, wavelength tuneability range 521-545 nm with the output power at the extreme ends of this range 420 and 220 mW correspondingly.

Automatic electronic-controlled mode locking self-start in fibre lasers with non-linear polarisation evolution.

The present work demonstrates a fibre-laser system with automatic electronic-controlled triggering of dissipative soliton generation mode. Passive mode locking based on the effect of non-linear polarisation evolution has been achieved through a polarisation controller containing a single low-voltage liquid crystal plate whose optimal wave delay was determined from analysis of inter-mode beat spectrum of the output radiation.